Package opennlp.tools.util.eval

Class FMeasure

java.lang.Object
opennlp.tools.util.eval.FMeasure
public final class FMeasure extends Object
The FMeasure is an utility class for evaluators which measure precision, recall and the resulting f-measure. Evaluation results are the arithmetic mean of the precision scores calculated for each reference sample and the arithmetic mean of the recall scores calculated for each reference sample.

  • Constructor Summary

    Constructors
    Constructor
    Description
    FMeasure()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    double
    getFMeasure()
    Retrieves the f-measure score.
    double
    getPrecisionScore()
    Retrieves the arithmetic mean of the precision scores calculated for each evaluated sample.
    double
    getRecallScore()
    Retrieves the arithmetic mean of the recall score calculated for each evaluated sample.
    void
    mergeInto(FMeasure measure)
    Merge results into fmeasure metric.
    static double
    precision(Object[] references, Object[] predictions)
    Calculates the precision score for the given reference and predicted spans.
    static double
    recall(Object[] references, Object[] predictions)
    Calculates the recall score for the given reference and predicted spans.
    String
    toString()
    Creates a human read-able String representation.
    void
    updateScores(Object[] references, Object[] predictions)
    Updates the score based on the number of true positives and the number of predictions and references.

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

  • Constructor Details

    • FMeasure

      public FMeasure()

  • Method Details

    • getPrecisionScore

      public double getPrecisionScore()
      Retrieves the arithmetic mean of the precision scores calculated for each evaluated sample.
      Returns:
      the arithmetic mean of all precision scores

    • getRecallScore

      public double getRecallScore()
      Retrieves the arithmetic mean of the recall score calculated for each evaluated sample.
      Returns:
      the arithmetic mean of all recall scores

    • getFMeasure

      public double getFMeasure()
      Retrieves the f-measure score. f-measure = 2 * precision * recall / (precision + recall)
      Returns:
      the f-measure or -1 if precision + recall <= 0

    • updateScores

      public void updateScores(Object[] references, Object[] predictions)
      Updates the score based on the number of true positives and the number of predictions and references.
      Parameters:
      references - the provided references
      predictions - the predicted spans

    • mergeInto

      public void mergeInto(FMeasure measure)
      Merge results into fmeasure metric.
      Parameters:
      measure - the fmeasure

    • toString

      public String toString()
      Creates a human read-able String representation.
      Overrides:
      toString in class Object
      Returns:
      the results

    • precision

      public static double precision(Object[] references, Object[] predictions)
      Calculates the precision score for the given reference and predicted spans.
      Parameters:
      references - the gold standard spans
      predictions - the predicted spans
      Returns:
      the precision score or NaN if there are no predicted spans

    • recall

      public static double recall(Object[] references, Object[] predictions)
      Calculates the recall score for the given reference and predicted spans.
      Parameters:
      references - the gold standard spans
      predictions - the predicted spans
      Returns:
      the recall score or NaN if there are no reference spans